Power transmission belt

Abstract

An endless power transmission belt has an elastomeric body portion, load carrying members embedded in the body portion, and a power transmitting surface integral with the body portion. The elastomeric body portion further includes material to mitigate unstable frictional behavior of the body portion responsible for initiating self-excited vibration at the power-transmitting surface.

What is claimed is: 
     
       1. In an endless power transmission belt having rubber elastomeric body portion, load carrying members embedded in said body portion and a power-transmitting surface integral with said body portion, the improvement wherein said elastomeric body portion further comprises means to stabilize the coefficient of friction and reduce pilling at said power-transmitting surface said means comprising the presence of a siloxane having a viscosity of about 2 to about 100 centistokes in the body portion at said power-transmitting surface. 
     
     
       2. The improvement of claim 1, wherein said stabilizing means comprises a siloxane material interspersed throughout said elastomeric body portion, said material having a low coefficient of friction compared to that of the elastomer, a low surface energy compared to that of the elastomer, and an effective kinetic mobility of sufficient activity to continuously refresh said power-transmitting surface with said material during use of said belt. 
     
     
       3. The improvement of claim 1, wherein said stabilizing means comprises a siloxane incorporated throughout said elastomeric body portion. 
     
     
       4. The improvement of claim 1, wherein said siloxane comprises a polysiloxane. 
     
     
       5. The improvement of claim 4, wherein said polysiloxane comprises polydimethylsiloxane. 
     
     
       6. The improvement of claim 1, wherein the endless power transmission belt is a synchronous belt. 
     
     
       7. The improvement of claim 1, wherein said siloxane has a viscosity of from about 5-20 centistokes. 
     
     
       8. The improvement of claim 7, wherein said siloxane comprises a polysiloxane having a viscosity of from about 10-20 centistokes at a 0.5-3.0 percent by weight loading. 
     
     
       9. The improvement of claim 1 wherein the endless power transmission belt is a V-belt or a multi-ribbed V-belt. 
     
     
       10. The improvement of claim 9 wherein embedded in the elastomeric body portion of the belt are textile fibers, such fibers being present at the power-transmitting surface of the belt. 
     
     
       11. An endless power transmission belt of the V- or multi-ribbed V-type having opposing friction surfaces comprising a rubber elastomeric body portion, tensile members embedded in said body portion, and a power-transmitting surface including said opposing friction surfaces, said power transmitting surface being integral with said body portion, and said elastomeric body portion including siloxane interspersed throughout the elastomer of said body portion in an amount and viscosity during use of the belt to continuously lubricate said friction surfaces to suppress noise and pilling. 
     
     
       12. The belt as claimed in claim 11, wherein said siloxane lubricant material has a low coefficient of friction compared to the elastomer, a low surface energy compared to the elastomer, and an effective kenetic mobility of sufficient activity to continuously migrate to said power-transmitting surface during use of said belt. 
     
     
       13. The belt as claimed in claim 12, wherein said siloxane comprises a polysiloxane having a viscosity of from about 2-100 centistokes. 
     
     
       14. The belt as claimed in claim 11, wherein said siloxane comprises a polysiloxane having a sufficiently effective viscosity so as to provide a rate of migration through said body portion to said power-transmitting surface to effectively suppress belt noise and reduce pilling at said power-transmitting surface. 
     
     
       15. The belt as claimed in claim 11, wherein said lubrication means comprises a polysiloxane incorporated throughout said elastomeric body portion. 
     
     
       16. The belt as claimed in claim 15, wherein said polysiloxane is present in a range in an amount of approximately 0.5-3.0 percent by weight in said body portion and has a viscosity in a range of about 5-20 centistokes. 
     
     
       17. In an endless power transmission belt having an elastomeric body portion, load carrying members embedded in said body portion and a power-transmitting surface integral with said body portion, the improvement wherein said elastomeric body portion further comprises means to stabilize the coefficient of friction at the power-transmitting surface of the belt, said means comprising polydimethylsiloxane. 
     
     
       18. In an endless power transmission belt having an elastomeric body portion, load carrying members embedded in said body portion and a power-transmitting surface integral with said body portion, the improvement wherein said elastomeric body portion further comprises a polysiloxane distributed throughout the elastomeric body portion said polysiloxane having a viscosity of 10-20 centistokes at a range of 0.5-3.0 percent by weight serving to stabilize the coefficient of friction of the power-transmitting surface of the belt.